Bumps [@openzeppelin/test-helpers](https://github.com/OpenZeppelin/openzeppelin-test-helpers) from 0.5.3 to 0.5.4.
- [Release notes](https://github.com/OpenZeppelin/openzeppelin-test-helpers/releases)
- [Changelog](https://github.com/OpenZeppelin/openzeppelin-test-helpers/blob/master/CHANGELOG.md)
- [Commits](https://github.com/OpenZeppelin/openzeppelin-test-helpers/compare/v0.5.3...v0.5.4)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>